remove support for non-ANSI compilation

*** 118,129 ****
  #if defined(_XPG6) && !defined(_VA_LIST)
  #define _VA_LIST
  typedef __va_list va_list;
  #endif  /* defined(_XPG6) && !defined(_VA_LIST) */
  
- #ifdef __STDC__
- 
  #if !defined(_STRICT_STDC) || defined(_XOPEN_SOURCE) || defined(__EXTENSIONS__)
  #if __cplusplus >= 199711L
  namespace std {
  #endif
  extern int iswalpha(wint_t);
--- 118,127 ----
*** 190,238 ****
  extern size_t mbsnrtowcs(wchar_t *_RESTRICT_KYWD, const char **_RESTRICT_KYWD,
      size_t, size_t, mbstate_t *_RESTRICT_KYWD);
  
  #endif  /* defined(_XPG7) || !defined(_STRICT_SYMBOLS) */
  
- #else /* __STDC__ */
- 
- #if !defined(_STRICT_STDC) || defined(_XOPEN_SOURCE) || defined(__EXTENSIONS__)
- extern  int iswalpha();
- extern  int iswupper();
- extern  int iswlower();
- extern  int iswdigit();
- extern  int iswxdigit();
- extern  int iswalnum();
- extern  int iswspace();
- extern  int iswpunct();
- extern  int iswprint();
- extern  int iswgraph();
- extern  int iswcntrl();
- extern  int iswctype();
- extern  wint_t towlower();
- extern  wint_t towupper();
- extern wchar_t *wcswcs();
- extern int wcswidth();
- extern int wcwidth();
- extern wctype_t wctype();
- #endif /* !defined(_STRICT_STDC) || defined(_XOPEN_SOURCE)... */
- 
- #if defined(_XGP7) || !defined(_STRICT_SYMBOLS)
- extern size_t wcsnlen();
- extern wchar_t *wcpcpy();
- extern wchar_t *wcpncpy();
- extern size_t wcsxfrm_l();
- extern int wcscoll_l();
- extern wchar_t *wcsdup();
- extern int wcscasecmp();
- extern int wcscasecmp_l();
- extern int wcsncasecmp();
- extern int wcsncasecmp_l();
- extern size_t mbsnrtowcs();
- #endif
- 
- #endif /* __STDC__ */
- 
  #ifdef  __cplusplus
  }
  #endif
  
  #endif  /* _WCHAR_H */
--- 188,197 ----